Rotary anode for x-ray tubes

ABSTRACT

A rotary anode for X-ray tubes, wherein the rotary system consisting of the plate, rotor and bearings is connected by springs with the casing of the tube. The invention is particularly characterized in that the plate and the rotor are mounted upon an axle to which a rotary ring of each of two bearings is connected, while the other rotary ring engages a tube provided with springs which provide a connection with the casing and have their own frequency which is substantially less than the driving frequency.

[ June 25, 1974 United States Patent 1191 Haberrecker et al.

[ ROTARY ANODE FOR X-RAY TUBES 2/1960 Zunick......... 313/60 [75]Inventors: Klaus Haberrecker; Stefan Giinther, n Karl Saalbach BrirnqryExaminer-Henna Assistant both of Erlangen, Germany [73] Assignee:Siemens Aktiengesellschait,

:l aw we o c& a e .d WT. V a mh am j Mr 2 h 2m Si FLA e n w an X r h m tA A [22] Filed:

A rotary anode for X-ray tubes, wherein the rotary system consisting ofthe plate, rotor and bearings is [30] Foreign Application Priority DataJune 2, 1972 connected by springs with the casing'of the tube. The

Germany........v..v...,............ 2226714 invention is particularlycharacterized in that the plate and the rotor are mounted upon an axleto which a rotary ring of each f two bearings is connect-edwhile Fieid313/60 the other rotary ring engages a tube provided wlth springs whichprovide a connection with the casing and have their own frequency whichis substantially less than the driving frequency.

[56] References Cited UNITED STATES PATENTS 2.671608 v 5/1954 Cordingly313/60 5 Claims, 2 Drawing Figures "aha ROTARY ANODE FOR X-RAY TUBESThis invention relates to a rotary anode for X-ray tubes, wherein therotary system consisting of the plate, the rotor and bearings isconnected by springs with the casing of the tube. Spring connections areprovided so that the rotary anode should not produce any vibrations ortransmit them outwardly.

In a known X-ray tube with a rotary anode at least one of the runningrings of the bearings is connected by a disc spring with itscorresponding structural part. In a tube of this type there isresiliency in the longitudinal direction of the axle but none in thetransverse direction. Thus oscillations of the rotary system are alwaystransmitted to the casing and thus to the cathode in which a glowingwire, namely a glow coil, is located. This coil then begins to swing andstrikes its cover representing a Wehnelt cylinder. Weldings can thentake place which will make the cathode and thus the tube unuseable.

An object of the present invention is to improve existing constructionsof this type.

In the accomplishment of the objectives of the present invention therotary system is separated from the casing and thus from the cathodewith respect to transmission of mechanical vibrations in that the plateand the rotor are mounted upon an axle to which one of the two runningrings of the bearings is connected, while the other ring engages a tubeprovided with springs which constitute a connection with the casing andwhich have own frequency which is considerably lower than the drivingfrequency.

In a tube of this type all rotating parts of the tube are mechanicallyseparated from other parts of the tube, since due to the spring partsthe amplitude resonance works in the opposite direction, so that thereis transmitted only a fraction of the vibration amplitude whichapproaches zero.

This arrangement prevents in a simple manner that vibrations of therotor could be transmitted to the cathode with resulting losses in thetube based upon the damage to the cathode. Furthermore outwardlyprojecting noises are dampened. In addition, any imbalance which cantake place is balanced out automatically since the springs permit a newsetting of the location of the rotary axle. It is merely necessary tomake certain that there is sufficient space for deviations between therotor and the support, as well as a sufficient resilient path makingpossible the deviation.

As separating resilient means can be used all elements which can preventthe transmission of vibrations. They can be, as already stated, anysprings which are effective between the rotation system and the casing.In a simple but effective construction of the present invention sheetsprings are used cut in the tube supporting the bearings. However, otherspring devices can be also suitable which make use of the resilientaction of spiral springs, etc.

According to an embodiment which is constructionally very easy and whichfacilitates the making of tubes, the axis of the plate is a centralshaft upon which sit the inner rotary rings of the two bearings, whileouter rings engage a tube the outer side of which carries the springs. Atube is attached to the casing which constitutes a plug socket intowhich the tube connected with the bearings is inserted and which is heldprimarily by the resulting pressure of the springs. To maintain apredetermined position indentations, grooves, beads, etc. are providedfor the springs. For this construction the rotational system ismanufactured separately from the rest of the tube and is inserted intothe casing after the other tube parts are finished. In case of aseparable casing the rotary system can easily exchanged at any time. Anequivalent solution is provided by providing the springs at the innerside of the outer casing.

The invention will appear more clearly from the following detaileddescription when taken in connection with the accompanying drawingshowing by way of example only, preferred embodiments of the inventiveidea.

In the drawing:

FIG. 1 is a section through an X-ray tube of the present invention andspecifically shows the arrangement of the resilient means at a tubeinterconnecting the bearings.

FIG. 2 is a partial section through a differently constructed upperbearing wherein the resilient means are arranged at a tube fixed to thecasing.

The X-ray tube with rotary anode shown in FIG. 1 has a cylindricalcasing l and a tube 2 fixed to a front surface of the casing and open tothe interior. This tube 2 carries the actual rotary system 3 whichincludes the two ball bearings 4 and 5. They hold the axle 6 in themiddle of the tube 7. This provides the connection of the rotary system3 through the tube 2 with the casing 1. The rotor 9 consists of copper;its interior is coated by a layer 10 which consists of iron and has athickness of about 5 mm. The iron can be also applied in the form of atube. The upper free end of the rotor 9 carries the part 11 of the axle6 upon which is located the actual rotary anode plate 12 consisting oftungsten.

The X-ray tube is operated in the known manner by actuating voltageapplied between the line 13 and the tube 2. By applying a heatingvoltage of 20 v. between the line 13 and one of the two other lines 14or 15 the plate 12 is struck by electrons, so that X-rays are producedwhich can be used in a known manner for making X-ray pictures, etc. Thenthe plate 12 rotates since from the outside a stator of known design isapplied to the casing 1 which produces a rotational moment in the rotor9 by means of an alternating field. This causes the rotation of the axle6 which rotates in bearings 4 and 5, the inner rotary rings 16 and 17 ofwhich lie upon the axle 6. The outer rotary rings 18 and 19 engage thetube 7. This tube 7 consists of iron and in annular zones parallel tothe bearings 4 and 5 has several outwardly bent tongue-like extensions.There are four of such tongues in each zone in this embodiment. Thedrawing shows at the upper bearing two tongues 20 and 21 and at thelower bearing two tongues 22 and 23. The insertion of the rotary system3 is limited by inwardly extending collars 23' which form a snap-ingroove for the springs 22, 23 and limit precisely the extent of theinsertion. By using spring steel which resists high temperatures as thematerial for the tube 7, the tongues 20 to 23 receive continuouslyresilient properties which produce a sufficiently firm hold to resistrotary frequencies developed in X-ray tubes and mechanical loadsresulting from supports as well as movements.

The section illustrated in FIG. 2 shows an outer tube 24 whichcorresponds to the tube 2 of FIG. 1 and which receives the springs. FIG.2 shows springs 26 and 27 provided close to the bearing 25 whichcorresponds to the bearing 4. These springs support the inner tube 28corresponding to the tube 7. At a location away from the bearing theconstruction of FIG. 2 has a further series of springs corresponding tothe springs 22 and 23 of FIG. 1, so as to provide a sufficiently stablehold. Grooves 29 constitute the fixing means into which snap the springs26, 27. In this construction similarly to that of FIG. 1, the axle 30 ofthe anode is separated from the casing by running rings. FIG. 2 showsrings 32 and 32 othe upper bearing 25.

What is claimed is:

1. An X-ray tube with rotary anode, comprising a casing, an anode platewithin said casing, a rotor, an axle connected with said plate and saidrotor, two spaced bearings, a tube enclosing a part of said axle, eachof said bearings having an inner ring carried by said axle and an outerring connected with said tube, and resilient means connecting said tubewith said casing and having own frequency which is substantially lowerthan the driving frequency.

2. An X-ray tube with rotary anode, according to claim 1, comprising atube carried by an end of said casing, the first-mentioned mentionedtube fitting into the second-mentioned tube, and wherein said axle is acentral shaft and said resilient means are carried by an outer surfaceof the first-mentioned tube.

3. An X-ray tube with rotary anode according to claim 2, wherein saidresilient means are tongues cut out of the first-mentioned tube.

4. An X-ray tube with rotary anode, comprising a casing, an anode platewith said casing, a rotor, an axle connected with said plate and saidrotor, two spaced bearings, a tube enclosing a part of said axle, eachof said bearings having an inner ring carried by said axle and an outerring connected with said tube, another tube enclosing thefirst-mentioned tube, and resilient means connecting thesecond-mentioned tube with said casing and having own frequency which issubstantially lower than the driving frequency.

5. An X-ray tube with rotary anode according to claim 4, wherein saidresilient means are tongues cut out of the second-mentioned tube.

1. An X-ray tube with rotary anode, comprising a casing, an anode platewithin said casing, a rotor, an axle connected with said plate and saidrotor, two spaced bearings, a tube enclosing a part of said axle, eachof said bearings having an inner ring carried by said axle and an outerring connected with said tube, and resilient means connecting said tubewith said casing and having own frequency which is substantially lowerthan the driving frequency.
 2. An X-ray tube with rotary anode,according to claim 1, comprising a tube carried by an end of saidcasing, the first-mentioned mentioned tube fitting into thesecond-mentioned tube, and wherein said axle is a central shaft and saidresilient means are carried by an outer surface of the first-mentionedtube.
 3. An X-ray tube with rotary anode according to claim 2, whereinsaid resilient means are tongues cut out of the first-mentioned tube. 4.An X-ray tube with rotary anode, comprising a casing, an anode platewith said casing, a rotor, an axle connected with said plate and saidrotor, two spaced bearings, a tube enclosing a part of said axle, eachof said bearings having an inner ring carried by said axle and an outerring connected with said tube, another tube enclosing thefirst-mentioned tube, and resilient means connecting thesecond-mentioned tube with said casing and having own frequency which issubstantially lower than the driving frequency.
 5. An X-ray tube withrotary anode according to claim 4, wherein said resilient means aretongues cut out of the second-mentioned tube.